Problem:    Using freed memory with cmdwin and BufEnter autocmd.
Solution:   Make sure pointer to b_p_iminsert is still valid.

Problem:    Using "end_lnum" with virtual text causes problems.
Solution:   Disallow using "end_lnum" with virtual text. (closes #11151)
            Also disallow "end_col" and "length".

Problem:    Cursor in wrong position with virtual text "above" and
            'showbreak'.
Solution:   Take the first character column into account. (closes #11149)

Problem:    Using freed memory with combination of closures.
Solution:   Do not use a partial after it has been freed through the
            funcstack.

Problem:    Text scrolled with 'nosplitscroll', autocmd win opened and help
            window closed.
Solution:   Skip win_fix_scroll() in more situations. (Luuk van Baal,
            closes #11150)

Problem:    In a :def function all closures in a loop get the same variables.
Solution:   Make a copy of loop variables used in a closure.

Problem:    In a :def function all closures in a loop get the same variables.
Solution:   Add ENDLOOP at break, continue and return if needed.

Problem:    Illegal memory access when replacing in virtualedit mode.
Solution:   Check for replacing NUL after Tab.

Problem:    "g0" moves to wrong location with virtual text "above".
Solution:   Compensate for the extra columns. (closes #11141)  Also fix "g$"

Problem:    In a :def function all closures in a loop get the same variables.
Solution:   Use a separate list of variables for LOADOUTER and STOREOUTER.
            Not copied at end of loop yet.